BY ARTIFICIAL DIVISION. 93 



behind where the two posterior branches of the intestine part 

 from the proboscis, (p,) the anterior half of the body will, in 

 order to become perfect again, have to reproduce the posterior 

 branches of the intestine, a new mouth and proboscis, and 

 the whole of the reproductive organs ; whilst the posterior half 

 must do the same for the anterior branch of the intestine, (c,) 

 and the main part, the so-called brain, of the nervous system. 

 These two figures (fig. 48, A, B) represent the 

 condition of the two halves after they had been 

 cut apart eleven days. On the 24th of Sep- 

 tember the division was made with a sharp J 

 knife ; and whilst the animal was under a mag- 

 nifying lens, in order that the precise line of the 

 cut might be seen clearly. The process of 

 reproduction was watched from day to day, and 

 the method of procedure carefully noted. As 

 has already been stated by others who have 

 performed this experiment, the two halves 

 crawled off, after the section, as if nothing had happened ; the 

 anterior part preceding an imaginary tail, and the posterior one 

 following an equally ideal head and brain. By frequent obser- 

 vations upon the newly developing parts, I ascertained that the 

 restored organs were not formed all at once, but gradually, as it 

 were bit by bit, in this wise. From the anterior half (A) a point 

 insensibly budded out at the cut end, and within this projec- 

 tion a clear spot (m] appeared, which eventually proved to be the 

 retiring chamber, or sheath of the proboscis when retracted 

 within the body ; next the proboscis, (;?,) with a gradually denn- 

 ing outline, made itself apparent, and at the same time irregular 



Fig. 48. The same as figure 47, after being cut in two and allowed to regen- 

 erate for eleven days. A, the anterior half; p, the new proboscis ; w, the cavity 

 into which the proboscis retracts ; c, the original anterior branch of the intes- 

 tine ; e, the new posterior branches of the same; B, the posterior half; p l , the 

 original proboscis ; e l , the original, posterior branches of the intestine ; c 1 , the 

 incipient anterior branch of the intestine ; d, the opening of the reproductive 

 organs. Original. 



